Cards (13)

    • Land plants

      • Autotrophs
      • Movement onto land by algal ancestors provided: unfiltered sun, more CO2, nutrient-rich soil, less herbivores and pathogens
      • Since 500 mya, land plants have diversified into >300,000 living species
      • Plants supply oxygen and are the ultimate source of food eaten by land animals
    • Derived traits of plants
      • Alternation of generations
      • Spores produced in sporangia
      • Apical meristems
    • Alternation of generations
      • Plants contain two different multicellular forms in their life cycle
      • Sporophyte (diploid) produces spores by meiosis
      • Gametophyte (haploid) produces gametes by mitosis
    • Spores produced in sporangia
      • Sporophyte (diploid) produces spores by meiosis
      • Spores are produced in sporangia
      • Diploid sporocytes undergo meiosis to produce haploid spores
      • Spore walls made of sporopollenin
    • Apical meristems
      Sites of continual growth
    • Bryophytes
      • Life cycle dominated by gametophyte (haploid)
      • Bryophytes include three phyla of herbaceous (nonwoody) plants: Marchantiophyta (Liverworts), Anthocerophyta (Hornworts), Bryophyta (Mosses)
    • Life cycles with dominant gametophyte
      • Haploid gametophyte grows from spores - "dominant" form
      • Gametes are produced in structures called gametangia via mitosis
      • During wet conditions, sperm produced in antheridia swim to eggs produced in archegonia
      • Depending on the species, antheridia and archegonia may be housed on a single gametophyte or separate male and female gametophytes
      • The zygote will grow into a mature diploid sporophyte - "reduced" form, completely dependent on the gametophyte for nutrients/energy, produces spores in sporangia, diploid sporocytes undergo meiosis to produce haploid spores
    • Liverworts
      • moss
    • Evolution of vascular tissues allowed plants to grow tall
      Living vascular plants are characterized by: Life cycles with dominant sporophytes, Vascular tissues (xylem and phloem), Well-developed roots and leaves
    • Life cycles with dominant sporophytes
      • Haploid spores produce mature gametophytes - reduced (2-5mm), Depending on the species antheridia and archegonia may be housed on a single gametophyte or separate male and female gametophytes
      • During wet conditions, sperm produced in the antheridia swim to the egg housed in the archegonia
      • The zygote will grow into a mature diploid sporophyte - "dominant" form, much larger than the gametophyte, sporangia house sporocytes that undergo meiosis to produce haploid spores
    • Vascular tissues: xylem and phloem
      • Xylem: conducts water and minerals, consists of dead cells (e.g. tracheids and vessel elements), cell walls strengthened by lignin
      • Phloem: distributes sugars, amino acids, and other organic products, consists of living cells
    • Roots and leaves
      • Roots: organs that anchor vascular plants, enable plants to absorb water and nutrients from the soil
      • Leaves: organs that increase the surface area of vascular plants, capture solar energy used in photosynthesis
    • Seedless vascular plants
      Two phyla: Lycophyta (club mosses, spike mosses, and quillworts), Monilophyta (ferns, horsetails, and whisk ferns)